Up to now in the prior art motor vehicle doors have primarily been made up or assembled from individual parts, i.e. the motor vehicle door consists of an integrally designed window frame and door frame and is provided with the necessary components such as window lifting mechanism, side window, lock, etc. In some motor vehicle doors, equipment such as the window lifting mechanism or lock, for example, are also pre-assembled on an equipment carrier. In this case the equipment carrier is attached to the motor vehicle door with disconnectable fixing agents so that it is possible in a simple manner to detach the equipment carrier from the door structure (window frame and door frame) for maintenance or repair purposes.
However, at present developments are heading towards the creation of bigger and bigger pre-assembly units at the automobile manufacturer in order to keep assembly times on the (main) assembly line low. As a result efforts are also being made with a car door to design the majority of components as a pre-assembly unit.
DE 199 42 644 A1 and DE 199 42 650 A1 describe a pre-assembly unit. In the printed matter referred to, the window lifting mechanism is connected directly to the equipment carrier in order to stabilize and fix it in position. If the pre-assembly unit is inserted into the door frame of a motor vehicle, then the window frame is connected to the door frame on one hand and also by way of screwed connections with the equipment carrier on the other. The window lifting mechanism always remains connected to the equipment carrier alone. Thus the problem arising in the prior art in cases of repair or for disassembly that even if the fixing means for joining the equipment carrier to the window frame on one hand and to the door frame on the other can be undone, it is not possible to remove it separately (i.e. on its own) because the window lifting mechanism is permanently connected to the equipment carrier, i.e. it would be necessary either to remove the window lifting mechanism including side window or to separate the whole pre-assembly unit with the window frame from the door frame. However, it is not desirable to undo the connection between the window frame and the door frame once this connection has been made. Thus the disassembly procedure for the former variation is complicated or even not possible at all due to the cramped conditions, and the other disassembly procedure involves major expenditure in terms of time and money and, furthermore, disconnection of the window frame from the door frame is not desirable (for example because of the tolerances already set up, the seal disposed between them, etc.).